Rotavirus A (RVA) is an important cause of acute gastroenteritis (AGE) in children. This study aims to investigate the molecular epidemiology of RVA children hospitalized with AGE in Chiang Rai, Thailand in 2018-2020 by RT-PCR. Of 302 samples, RVA was detected in 11.6% (35 samples): 11.3% (19/168) in 2018-2019 and 11.9% (16/134) in 2019-2020. Surprisingly, G8P[8] was detected as the predominant genotype at 68.4% in 2018-2019 and 81.2% in 2019-2020. In addition, other genotypes were also detected, including G1P[8] (15.8%), G2P[4] (5.3%), G3P[8] (10.5%) in 2018-2019 and G9P[8] (18.8%) in 2019-2020. Analysis of genomic constellation of G8P[8] strains, represented by RVA/Human-wt/ THA/5CR11/2019/G8P[8], revealed a DS-1-like genetic backbone: G8-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Phylogenetic analysis of the VP7 gene showed that the DS-1-like G8P[8] strains clustered in a distinct sublineage A together with 13 G8P[8] strains reported from Thailand and China, and these sublineage A G8P[8] strains contained unique amino acid substitutions in two positions (A125S and N147D) on the VP7 antigenic epitopes. Homology modeling of the VP7 capsid protein confirmed that these two amino acid changes were located on the surface exposed area of the virion. Phylogenetic trees of the VP1, VP6, NSP2, NSP3, and NSP4 genes have demonstrated that DS-1-like G8P[8] strains in the present study and 51 DS-1-like G8P[8] reference strains published formerly clustered in separate lineages. To the best of our knowledge, this is the first report of the emergence of novel DS-1-like G8P[8] strains that might have evolved genetically through reassortment events with locally or globally circulating genotypes.